1. Field of the Invention
The present invention relates to an image display apparatus and an image display method in which a user is capable of performing gamma adjustment easily and in detail with respect to images such as picture contents.
2. Description of Related Art
In recent years, there is an increasing demand for image display apparatuses capable of displaying a vibrant picture on a large screen, along with the spread of digital versatile disks (DVDs), blu-ray disks (BDs), and the like. Examples of such image display apparatuses include projectors that are projection type image display apparatuses, which can be combined with a screen to display a large screen picture.
Of the projectors, a projector, particularly, for home use that is commercially available is being requested to have higher image quality and more functions every year, along with an increase in size of a screen. Therefore, the projector tends to have various functions of adjusting images so that a user can adjust images such as picture contents in accordance with the user's preference. The functions of adjusting images include gamma adjustment, i.e., a function of adjusting the level of an optical output with respect to the level of a video signal input to an image display apparatus. A device has also been proposed, which has a function for allowing a user to adjust a level of an optical output with respect to the level of an input signal of a particular picture while watching a screen of an on-screen menu, for performing gamma adjustment.
An example of the function of adjusting images mounted on a projector is described in US 2007/0046596 A1, and JP 2009-171192 A. The function of gamma adjustment described in this document is one allowing a user to adjust an optical output level with respect to each input level at positions of a plurality of particular input signal levels prepared previously on a producer side.
However, in the function of gamma adjustment mounted on a projector described in the above-mentioned document, the user can adjust an optical output level only at positions of input signal levels prepared previously on a producer side. Therefore, there is a limit for a user to adjust an optical output level with the input signal level preferred by the user, which makes it difficult for the user to perform adjustment freely and in detail. Further, this function is limited to the adjustment of Y (luminance), and therefore, it is impossible to perform adjustment with each color of R, G, and B.